This invention relates to optical fibre connectors and particularly to a method and apparatus for enabling an optical fibre cable having a plastics outer sleeve to be optically coupled to another optical fibre cable or to an active device.
Conventionally, in order to enable such optical coupling of an optical fibre cable, a tubular connector body is provided having one end for receiving an optical fibre and carrying at the other end connection means for coupling to another connector body. A ferrule for supporting an optical fibre is mounted within the other end of the connector body. A settable adhesive material, usually a resin, is injected into the ferrule and an optical fibre cable is then inserted into the one end of the connector body so that an exposed end portion of the optical fibre passes into the ferrule. The settable resin is then cured by a heat treatment to secure the optical fibre within the ferrule. This heat treatment involves subjecting the optical fibre cable and connector body to relatively high temperatures of, for example, about 100 degrees Celsius for about ten minutes and it is then necessary to allow the connector body to cool down before it can be handled. This heat treatment is thus time-consuming. In addition, the hardness of the cured resin tends to be inconsistent and this heat treatment may induce stress in the optical fibre. The hot resin exhibits a very low viscosity and may flow by capillary action into areas where it is not desired. Moreover, the protective plastics outer sleeve of the optical fibre cable is normally formed of a very inert and slippery plastics material such as PTFE (polytetrafluoroethylene) and does not easily adhere to the resin. It is therefore possible that the optical fibre itself may be securely fixed in place within the ferrule but that the plastics outer sleeve may be free to move within the tubular connector body so that any load applied on the cable may cause the plastics outer sleeve to move relative to the optical fibre resulting in undue stresses and strains on the optical fibre and possibly even causing the optical fibre to break.